The present invention relates to an electrolysis installation, such as an installation adapted for the industrial production of hydrogen and oxygen by electrolysis of water under pressure.
In the electrolysis installations known at present, for example as described in the French Patent Application filed on the Apr. 2, 1979 by the Applicant under No. 79 08694, the return circuits of anolyte and catholyte originating from the separators are united in one and the same pipeline which makes it possible thus to obtain equal densities of potash at the input of the electrolyzer at the anode side and at the cathod side. This joining of the return circuits of degassed electrolyte makes it possible, by ensuring equal densities of potash at each of the two inlets of the electrolyzer, to avoid a drop in the performance of the electrolyzer in the course of its operation, which would be due to the increase in the density of potash at the cathode side and the correlative reduction of this at the anode side. It is actually known that the electrolysis reaction leads to a loss of potash and a gain in water at the anode side and vice versa at the cathode side; now the resistivity of the electrolyte depends on the density of this in potash, and increased if there is a substantial deviation at one side or the other of the optimum density. It is therefore essential, in order to operate with a satisfactory performance, always to keep the potash densities at the inlets of the electrolyzer close to the optimum density corresponding to the minimum of resistivity of the electrolytic mixture.
With the known instalations, it is essential, in order to avoid the risks of explosions due to possible mixtures of hydrogen gas and oxygen, to be equipped with very effective liquid-gas separators, which should degas the whole of the electrolyte flow in circulation. Such gas removers are bulky and expensive and it would be desirable to be able to equip the electrolysis installation with less sophisticated gas removing devices.